Transmissions are used in a variety of applications to change the speed and torque provided by an engine or prime mover. One popular application of transmissions is in an automobile. In an automobile, the transmission is connected between the engine and the drive wheels or tires.
Prior art automobiles utilize fixed ratio transmissions. These transmissions have a set of gears that provide a few fixed and discrete speed ratios between the input from the engine and the output to the tires. Engine rpm (revolutions per minute) varies over a wide range for each speed ratio. Because the engine must operate over a wide range of speeds, its overall efficiency is reduced.
Continuously variable transmissions offer a way to boost engine efficiency. Unlike fixed ratio transmissions, continuously variable transmissions offer a wide range of speed ratios between the input from the engine and the output to the tires. This allows the engine to operate over a narrow range of optimum rpm's, wherein the engine efficiency can be increased. By varying the speed ratio, the engine speed can be maintained in its optimum range, even for a variety of driving conditions, thereby improving fuel efficiency.